Presently available apparatus designed for use in treating the human uterus are typically rigid devices. Such apparatus may cause discomfort to the patient and can lead to perforation of internal tissues. Additionally, the use of such rigid tools may require dilation of the cervix, repositioning of the uterus and use of clamps for stabilization. These procedures are often painful and can induce uterine bleeding.
U.S. Pat. No. 3,527,203 refers to an apparatus for irrigating a body cavity which has an inlet tube, an outlet tube, and a sealing member. The tubes are made from a rigid plastic material, and have rough-edged apertures which are designed to facilitate the collection of tissue samples.
U.S. Pat. No. 3,948,270 refers to a uterine cannula for human uterine elevation, which comprises a rigid tube positioned inside a Foley catheter. Due to its rigidity, this type of cannula cannot follow the natural contours of the uterus.
U.S. Pat. No. 3,095,871 refers to a diagnostic tool for the human uterus. The tool comprises a hard rubber catheter, used in combination with a rigid stylet introducer.
Rigid uterine-invasive apparatus are also used in the field of animal husbandry. For example, U.S. Pat. No. 3,854,470 refers to a rigid pipette containing a catheter for the insertion of ova into hooved mammals. U.S. Pat. Nos. 4,178,936 and 4,004,588 refer to uterine catheters, used in combination with rigid introducers that penetrate the uterus for ova recovery, particularly in cattle.
A non-rigid catheter has been developed to facilitate non-surgical procedures for treating the human uterus. This apparatus causes virtually no discomfort to the patient and does not require the use of external introduction means or anesthesia. This apparatus combines stiffness and flexibility to good advantage in such non-surgical procedures.
Although this non-rigid catheter can be employed in the recovery of pre-implantation embryos for human embryo transfer or artificial embryonation, it is somewhat disadvantaged in those applications because in operation it may lose lavage fluid out the oviducts and it may become obstructed by uterine tissue or mucus and, when obstructed may cause the loss of lavage fluid out the cervix. Any loss of such lavage fluid risks loss of the embryo. Moreover, when the fluid loss is through the oviducts an ectopic pregnancy may result. In addition, this catheter is not steerable within the uterine cavity, making it difficult to lavage the complete uterine surface. As a result, the recovery of pre-implantation embryos is lower than desired using this catheter.
Because of the pre-implantation embryo recovery efficiency of that catheter in processes for non-surgical human embryo transfer and artificial embryonation is lower than desired, the full potential of those processes in treating human infertility, in avoiding genetic or hereditary diseases and in permitting prenatal adoptions has not been fully realized.